Many fluids, such as photo-resist liquids used in the micro-electronics industry, are exceedingly expensive. These liquids must be filtered immediately prior to being used or impurities in the liquids can damage the micro-electronic components being fabricated.
Conventional filters have many problems associated with them. For example, many conventional filters have relatively large volumes within them, e.g., hold up volumes, which collect and trap the liquid. These hold up volumes are expensive because the expensive liquid trapped in the hold up volumes is discarded when the filter is discarded. Further, many of these filters have dead zones where the flow of fluid stagnates. When a liquid such as a photo-resist liquid stagnates it can undergo chemical and/or physical changes which can be detrimental to the fabrication process. In addition, when the liquid is first pumped through a filter having large hold up volumes and dead zones, the amount of time and the amount of wasted liquid required to fill the hold up volumes and the dead zones before a clean filtered liquid emerges from the outlet of the filter can be considerable.